This invention relates to an apparatus for filling and closing sacks, for example sacks made of thermoplastic sheet material which may be formed with gussets. Apparatus for this purpose may for example, comprise a pair of grippers for gripping lateral portions of the sacks adjacent their opening-defining edges, wherein the grippers of each pair are movable toward and away from each other, a pair of suction cups for pulling the side walls of the sacks apart adjacent the opening-defining edges between the grippers, a filling pipe, which is adapted to be lowered into and lifted out of the opened sacks, and a welding device for forming a transverse weld seam, to close the opening-defining edges, after they have been pulled taut to contact each other by a movement of the grippers away from one another.
Known apparatus of the above kind is commonly provided with a conveyor for conveying the sacks from a first station, (which normally constitutes a feeding station in which the conveyor receives the individual sacks after they have been provided with a bottom seam,) to a filling station, and which in a succeeding conveying step conveys the filled sacks to a welding station, in which the tautened opening-defining edges of the filled sacks are provided with a transverse weld seam. The sacks are usually released by the conveyor in the welding station or in a further conveying step succeeding the welding station and are usually conveyed further by another conveyor. If the sacks consist of paper, a sewing machine for closing the opening-defining edges of the sacks is provided rather than a welding means.
Known apparatus of the kind described usually has an expensive structure, particularly owing to the provision of the conveyor for conveying the sacks through the various stations.